The present invention relates generally to the field of molecular biology, cell biology and medicine and more specifically to Parkinson's disease.
Parkinson's disease (PD) is a major neurodegenerative disease characterized by muscle rigidity, tremor, and bradykinesia (Dunnett and Bjorklund, Nature 399:A32-A39 (1999)). Other symptoms such as postural deficits, gait impairment, and dementia are also observed in a subpopulation of PD patients. Although the majority of idiopathic PD cases are sporadic and probably influenced by environmental factors, familial aggregation of cases and rare mendelian inheritance of PD traits evince the importance of genetics.
Parkinsonism is a clinical syndrome dominated by four cardinal signs: tremor at rest, bradykinesia, a decrease in spontaneity and movement, rigidity, and postural instability. Less prominent manifestations concern the mood and intellect, autonomic function and the sensory system. The average age at onset is 55 years, with about 1% of persons 60 years of age or older having the disease. Men are affected more frequently than women.
Resting tremor and bradykinesia are the most typical parkinsonian signs and are virtually synonymous with the diagnosis. Bradykinesia accounts for most of the associated parkinsonian symptoms and signs: general slowing down of movements and of activities of daily living; lack of facial expression (hypomimia or masked facies); staring expression due to decreased frequency of blinking; impaired swallowing, which causes drooling; hypokinetic and hypophonic dysarthria; monotonous speech; small handwriting (micrographia); difficulties with repetitive and simultaneous movements; difficulty in arising from chair and turning over in bed; shuffling gait with short steps; decreased arm swing and other automatic movements; and start hesitation and freezing. Freezing, manifested by sudden and often unpredictable inability to move, is one of the most disabling of all parkinsonian symptoms.
As the population ages and the number of people over 60 increases, it is likely that a growing number of individuals will develop Parkinson's disease. Although treatments are available for treating Parkinson's disease, many of these treatments use drugs having undesirable side effects. Given the debilitating symptoms associated with Parkinson's disease, it is important to understand the cause(s) of Parkinson's disease so that additional modes of treatment can be developed.
Thus, there exists a need to identify and characterize genes and gene products associated with the development of Parkinson's disease. The present invention satisfies this need and provides related advantages as well.